Cloudy weather affecting simazine?

I've been spraying simazine at 1 qt per acre on my Bermuda for fall pre. Started about 2 weeks ago and should finish today. Seeing some yellowing but not total kill

I'm seeing slow results. The temps have been between 50-80 most every day. We have been in a very cloudy weather pattern with almost no sun. It drizzled for a week and we got measurable amounts of rain 2-3 times. Lawns are stil 60-70% or higher green.

I'm assume because the mode of action of simazine. that if there is little sun the plant produces very little chlorophyll and would result in a mug slower kill?Posted via Mobile Device

Correct. If the weeds are not photosynthesizing rapidly, simazine will be very slow. It is useless for me to apply triazine or SU herbicides in weather that is not conducive to vigorous growth. The old chemistries like phenoxys or Quats are not as affected by bad weather.

Are only older chemistries affected by temperature? If temperature impacts plant growth, all herbicides will be impacted.

By "Quats", do you mena PSI inhibitors? Paraquat and diquat are known to react in a matter of hours, even in complete darkness. Sure, they work minutes quicker in direct sunlight, but can you qualify it as "slow" if it takes 60 minutes vs 45 minutes?

Cloudy weather will impact triazines, but just the cloudy weather alone usually isn't the culprit. It is a combination of temperature, moisture, and sunlight. Triazines are very soluble in water and steady drizzles over time ofter reduce root uptake.

In short, its just gonne take a little bit longer than you're used to. That's all.

Hey azz, why don't you read before you react. No one mentioned "temperature" but you. Green mentioned photosynthesis. He also said "quats" would be "affected less" so he didn't "qualify" anything as "being slow" pertaining to "quats". For a phd no it all label writer, you sure need to read and comprehend a little better. Now go kick your dog or something to release that pent up frustration, because greendoc is appreciated here unlike you. Your ending is perfect.......it's exactly what greendoctor said in the first place

Are only older chemistries affected by temperature? If temperature impacts plant growth, all herbicides will be impacted.

By "Quats", do you mena PSI inhibitors? Paraquat and diquat are known to react in a matter of hours, even in complete darkness. Sure, they work minutes quicker in direct sunlight, but can you qualify it as "slow" if it takes 60 minutes vs 45 minutes?

Cloudy weather will impact triazines, but just the cloudy weather alone usually isn't the culprit. It is a combination of temperature, moisture, and sunlight. Triazines are very soluble in water and steady drizzles over time ofter reduce root uptake.

In short, its just gonne take a little bit longer than you're used to. That's all.

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"there's nothing more permanent than a temporary government program" Ronald Reagan

If you disagree, just say so, and explain your point of view. I appreciate you, Skip.

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I disagree with someone attacking someone repeatedly for no apparent reason. The "where did you get your phd" crap is what we don't need here. If skippy wants to help an original poster with an answer without acting like the professor among students things would be fine. Instead he attacks one of the most knowledgeable guys here who goes out of his way to help whenever possible, and never says a bad word to anyone. You can appreciate skippy all you want riggle but I think your in the wrong camp on this one.

"there's nothing more permanent than a temporary government program" Ronald Reagan

I know that in grassmasterwilson's location, it is turning from fall into winter. It sure isn't hot and cloudy where he is. Triazines are not the same in warm, sunny weather. Guess that is why there are now specific dates when they may be applied. Although I never had a problem with simazine or atrazine between June and September before there were date restrictions. Now why would someone apply that at that time of year? How about because those products are safe on newly plugged or sprigged grasses. Unlike Ronstar, which cannot be used on residential lawns or the DNA herbicides which will prune the roots off of the new grass. Or that if applied with the now restricted MSMA, it was a very good treatment for grassy weeds that also broke the cycle of those grassy weeds re taking a newly controlled area that did not inhibit tack down of zoysia or bermuda stolons crawling in from surrounding areas.

I know that in grassmasterwilson's location, it is turning from fall into winter. It sure isn't hot and cloudy where he is. Triazines are not the same in warm, sunny weather. Guess that is why there are now specific dates when they may be applied. Although I never had a problem with simazine or atrazine between June and September before there were date restrictions. Now why would someone apply that at that time of year? How about because those products are safe on newly plugged or sprigged grasses. Unlike Ronstar, which cannot be used on residential lawns or the DNA herbicides which will prune the roots off of the new grass. Or that if applied with the now restricted MSMA, it was a very good treatment for grassy weeds that also broke the cycle of those grassy weeds re taking a newly controlled area that did not inhibit tack down of zoysia or bermuda stolons crawling in from surrounding areas.

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Why are the zines restricted in the summer months, what possible negative effects would one see? Just wondering.